Display device substrate, display device, electronic apparatus, and method for manufacturing display device substrate

ABSTRACT

A first substrate includes: a first base material including an insulating layer; and a partition wall disposed on the insulating layer. The insulating layer and the partition wall are formed of a resin material. The partition wall has a higher hardness than the insulating layer. A protective film that protects the insulating layer is disposed on a surface of the insulating layer. A portion of the protective film is located between the partition wall and the insulating layer.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application havingSer. No. 16/826,374 filed on Mar. 23, 2020 (Publication No.2020/0218125), which is a continuation of U.S. patent application Ser.No. 15/259,165 filed on Sep. 8, 2016 (Publication No. 2017/0082904) nowU.S. Pat. No. 10,599,004 issued on Mar. 24, 2020. The entire disclosuresof the prior applications are hereby incorporated by reference herein intheir entireties.

BACKGROUND Technical Field

The present invention relates to a display device substrate, a displaydevice, an electronic apparatus, and a method for manufacturing adisplay device substrate.

Related Art

Electrophoretic display devices in which particles having charges movein a dispersion medium are widely used. The electrophoretic displaydevice has less screen flicker, and therefore is used as a displaydevice for viewing an electronic book, or the like. This type ofelectrophoretic display device is disclosed in JP-A-2007-240679.According to JP-A-2007-240679, the electrophoretic display deviceincludes a pair of substrates disposed with electrodes. A dispersionmedium containing colored charged particles is disposed between theelectrodes. A partition wall is disposed in a grid shape between thesubstrates, and rooms are partitioned by the partition wall. A distancebetween the substrates is kept by the partition wall.

In the room, the colored charged particles are charged. By applyingvoltages to a pair of electrodes disposed in the substrates facing eachother, the colored charged particles are attracted to one of theelectrodes. Next, by changing the voltages of the electrodes, theposition of the colored charged particles is changed.

Pixel electrodes are disposed in one of the substrates, and the pixelelectrode serves as one pixel. By controlling the position of thecolored charged particles for each of the pixels, a predetermined figurecan be displayed.

In JP-A-2007-240679, an insulating film covered by an inorganic materialis disposed on a surface of the one substrate. The partition wall isdisposed on the insulating film. The material of the partition wall is acardo polymer, which is one kind of resin materials. After thedispersion medium is disposed in the room within the partition wall, thepair of substrates are combined together. When the pair of substrate arecombined together, a load is applied between the substrates. In thiscase, since the partition wall and the insulating film are made of thematerials having different properties, the partition wall and theinsulating film are not securely bonded together. Thus, when a load isapplied to the partition wall, the partition wall and the insulatingfilm may peel from each other or may be shifted to each other. In thiscase, the partition wall collapses or crushes, and therefore, there is aneed for a display device substrate, in which the partition wall isinhibited from collapsing or crushing even when a load is appliedbetween the substrates.

SUMMARY

An advantage of some aspects of the invention is to solve at least apart of the problems described above, and the invention can beimplemented as the following forms or application examples.

Application Example 1

A display device substrate according to this application exampleincludes: a substrate including an insulating layer, and a partitionwall disposed on the insulating layer, wherein the insulating layer andthe partition wall are formed of a resin material, and the partitionwall has a higher hardness than the insulating layer.

According to this application example, the display device substrateincludes the substrate, and the substrate is disposed with theinsulating layer. The partition wall is disposed on the insulatinglayer. The insulating layer and the partition wall are formed of a resinmaterial. Thus, compared with the case where one of the insulating layerand the partition wall is an inorganic material, the insulating layerand the partition wall can be fixed together at high strength. Further,the partition wall has a higher hardness than the insulating layer, andtherefore has strength. As a result, even when a load is applied to thepartition wall, it is possible to inhibit the partition wall fromcollapsing or crushing.

Application Example 2

In the display device substrate according to the application example, itis preferable that a protective film that protects the insulating layeris disposed on a surface of the insulating layer.

According to this application example, the protective film protectingthe insulating layer is disposed on the surface of the insulating layer.Thus, since the insulating layer and a chemical liquid constituting adisplay device do not come in contact with each other, the chemicalliquid or the insulating layer can be prevented from being damaged.

Application Example 3

In the display device substrate according to the application example, itis preferable that the protective film includes an opening, and that thepartition wall is disposed so as to close the opening.

According to this application example, the partition wall is disposed soas to close the opening of the protective film, so that a chemicalliquid constituting a display device is inhibited from coming in contactwith the insulating layer by the protective film, and also that thepartition wall made of resin and the insulating layer made of resin canbe fixed together while being in contact with each other.

Application Example 4

In the display device substrate according to the application example, itis preferable that the substrate includes one pixel electrodecorresponding to one pixel, and that the partition wall is disposed tosurround the pixel electrode.

According to this application example, the substrate is disposed withone pixel electrode corresponding to one pixel. The partition wall isdisposed to surround the pixel electrode. In this case, compared withthe case where the partition wall surrounds a plurality of pixelelectrodes, the area surrounded by the partition wall is reduced. Thus,since the area within the partition wall is small, the strength of thepartition wall can be increased. As a result, even when a load isapplied to the partition wall, it is possible to inhibit the partitionwall from collapsing or crushing.

Application Example 5

In the display device substrate according to the application example, itis preferable that a circuit portion that is electrically connected tothe pixel electrode is disposed between the substrate and the insulatinglayer.

According to this application example, the circuit portion electricallyconnected to the pixel electrode is provided between the substrate andthe insulating layer. Thus, it is possible to inhibit the circuitportion from being eroded by a chemical liquid or the like constitutinga display device.

Application Example 6

In the display device substrate according to the application example, itis preferable that the insulating layer is a planarizing layer.

According to this application example, since the insulating layer is aplanarizing layer, the pixel electrode can be formed into a flat shape,and thus display quality can be improved.

Application Example 7

A display device according to this application example includes: thedisplay device substrate described above, a transparent sealing membersupported by the partition wall, a counter electrode disposed on thetransparent sealing member; a circuit portion located between thesubstrate and the insulating layer and connected to a pixel electrode;and an electrophoretic dispersion liquid sealed in a space formed by thepartition wall, the transparent sealing member, and the substrate.

According to this application example, the display device includes thedisplay device substrate, and the transparent sealing member issupported by the partition wall. The counter electrode is disposed onthe transparent sealing member. The display device substrate is disposedwith the partition wall, and the electrophoretic dispersion liquid isdisposed in a pixel region surrounded by the partition wall. Thus, thepartition wall is located between the display device substrate and thecounter electrode. Since the partition wall is less likely to collapseor crush even when a load is applied, the display device substrate, andthe transparent sealing member and the counter electrode can be easilyassembled.

Application Example 8

An electronic apparatus according to this application example includes:the display device described above; and a control unit that controls thedisplay device.

According to this application example, the control unit controls thedisplay device in the electronic apparatus. Since the display device isless likely to collapse or crush even when a load is applied to thepartition wall, the display device is a device in which the displaydevice substrate and the transparent sealing member can be easilyassembled. Thus, the electronic apparatus can be a device including thedisplay device in which the display device substrate and the transparentsealing member can be easily assembled.

Application Example 9

A method for manufacturing a display device substrate according to thisapplication example includes: disposing an insulating layer of a resinmaterial on a substrate; disposing a protective film on the insulatinglayer; removing a portion of the protective film; and disposing apartition wall of a resin material to cover the insulating layer at aplace where the portion of the protective film is removed.

According to this application example, the insulating layer of a resinmaterial is disposed on the substrate. Then, the protective film isdisposed on the insulating layer, and a portion of the protective filmis removed. Thus, a portion of the insulating layer is exposed. Thepartition wall of a resin material is disposed to cover the exposedinsulating layer. Thus, since the insulating layer of a resin materialand the partition wall of a resin material are connected to each other,the insulating layer and the partition wall can be securely connected.As a result, even when a load is applied to the partition wall in alater step, it is possible to inhibit the partition wall from collapsingor crushing.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described with reference to the accompanyingdrawings, wherein like numbers reference like elements.

FIG. 1 is a schematic perspective view showing the structure of anelectrophoretic display device according to a first embodiment.

FIG. 2 is a schematic plan view showing the structure of theelectrophoretic display device.

FIG. 3 is a partial schematic exploded perspective view showing thestructure of the electrophoretic display device.

FIG. 4 is a schematic sectional side elevation showing the structure ofthe electrophoretic display device.

FIG. 5 is a schematic plan view of a main portion for explaining therelationship between a pixel and a partition wall.

FIG. 6 is an electrical control block diagram of the electrophoreticdisplay device.

FIG. 7 is a schematic sectional side elevation showing the structure ofthe electrophoretic display device.

FIG. 8 is a schematic sectional side elevation showing the structure ofthe electrophoretic display device.

FIG. 9 is a flowchart of a method for manufacturing the electrophoreticdisplay device.

FIG. 10 is a schematic view for explaining the method for manufacturingthe electrophoretic display device.

FIG. 11 is a schematic view for explaining the method for manufacturingthe electrophoretic display device.

FIG. 12 is a schematic view for explaining the method for manufacturingthe electrophoretic display device.

FIG. 13 is a schematic view for explaining the method for manufacturingthe electrophoretic display device.

FIG. 14 is a schematic view for explaining the method for manufacturingthe electrophoretic display device.

FIG. 15 is a schematic view for explaining the method for manufacturingthe electrophoretic display device.

FIG. 16 is a schematic view for explaining the method for manufacturingthe electrophoretic display device.

FIG. 17 is a schematic view for explaining the method for manufacturingthe electrophoretic display device.

FIG. 18 is a schematic view for explaining the method for manufacturingthe electrophoretic display device.

FIG. 19 is a schematic sectional side elevation showing the structure ofan electrophoretic display device according to a second embodiment.

FIG. 20 is a schematic perspective view showing the structure of anelectronic book according to a third embodiment.

FIG. 21 is a schematic perspective view showing the structure of awristwatch.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

In embodiments, an electrophoretic display device and a distinct exampleof manufacturing the electrophoretic display device will be describedaccording to the drawings. Members in the drawings are illustrated ondifferent scales for each of the members in order to show the members inrecognizable sizes on the drawings.

First Embodiment

An electrophoretic display device according to a first embodiment willbe described according to FIGS. 1 to 18. FIG. 1 is a schematicperspective view showing the structure of the electrophoretic displaydevice. FIG. 2 is a schematic plan view showing the structure of theelectrophoretic display device.

As shown in FIG. 1, the electrophoretic display device 1 as a displaydevice has a structure in which a first substrate 2 as a display devicesubstrate and a second substrate 3 are stacked on top one another. Thethickness direction of the first substrate 2 and the second substrate 3is defined as a Z direction, and directions along the side surfaces ofthe first substrate 2 are defined as an X direction and a Y direction.The second substrate 3 is located on the +Z direction side. When viewingthe electrophoretic display device 1, a viewer views the electrophoreticdisplay device 1 from the +Z direction side. A surface of the secondsubstrate 3 on the +Z direction side is an image display surface 3 a.The first substrate 2 has a shape longer in the −Y direction than thesecond substrate 3. On the −Y direction side of the first substrate 2, aflexible cable 4 is disposed on a surface of the first substrate 2 onthe +Z direction side. The flexible cable 4 is connected to a drivecircuit (not shown), from which a power source and a drive signal aresupplied through the flexible cable 4.

As shown in FIG. 2, a partition wall 5 is disposed between the firstsubstrate 2 and the second substrate 3 in the electrophoretic displaydevice 1. The partition wall 5 has a grid shape and defines pixelregions 6. The dimensions of the partition wall 5 are not particularlylimited; however, for example, the width thereof is 3 to 5 μm, and theheight thereof is 30 μm in the embodiment.

In the drawing, 15 pixel regions 6 in the X direction and 10 pixelregions 6 in the Y direction are arranged side by side for clarity ofillustration. The number of the pixel regions 6 is not particularlylimited; however, for example, 320 pixel regions in the X direction and250 pixel regions in the Y direction are arranged side by side in theembodiment.

The size of the pixel region 6 is not particularly limited; however, forexample, the length thereof in the X direction is 50 to 100 μm, and thelength thereof in the Y direction is 50 to 100 μm, in the embodiment.Also the size of the electrophoretic display device 1 is notparticularly limited; however, for example, the length of the firstsubstrate 2 in the X direction is 30 to 50 mm, and the length thereof inthe Y direction is 20 to 40 mm, in the embodiment.

In the first substrate 2, a first semiconductor element 7 as a circuitportion is disposed in each of the pixel regions 6. The firstsemiconductor element 7 is an element that performs switching, andchanges a voltage to be applied to the pixel region 6. Since the firstsemiconductor element 7 exists in each of the pixel regions 6, thenumber of the first semiconductor elements 7 is the same as the numberof the pixel regions 6. When a predetermined pattern is displayed on theimage display surface 3 a, one pixel region 6 serves as one pixel 8. Ona surface of the first substrate 2 on the +Z direction side, a signaldistributing unit 9 is disposed between the second substrate 3 and theflexible cable 4. The signal distributing unit 9 changes a signal to beoutput to the first semiconductor element 7.

FIG. 3 is a partial schematic exploded perspective view showing thestructure of the electrophoretic display device, in which some portionsof the electrophoretic display device 1 are separated in the Zdirection. As shown in FIG. 3, the first substrate 2 includes a firstbase material 10. Examples of materials used for the first base material10 can include glass, plastic, ceramic, and silicon. The first basematerial 10 is arranged on the side opposite to the image displaysurface 3 a, which can be seen from the +Z direction, and therefore, thematerial of the first base material 10 may be opaque.

An element layer 11 is disposed on the first base material 10. In theelement layer 11, voltage supply lines 7 a, control signal lines 7 b,the first semiconductor elements 7, first through-electrode 7 d, and thelike are disposed. The first semiconductor element 7 is a thin filmtransistor (TFT) element, and is an element that performs switching. Aninsulating layer 12 is disposed on the element layer 11, and aprotective film 13 and pixel electrodes 14 are stacked in this order onthe insulating layer 12. The insulating layer 12 is a layer thatinsulates the element layer 11 from the pixel electrodes 14. Theprotective film 13 is a layer that protects the insulating layer 12. Thefirst through-electrode 7 d in the element layer 11 is connected withthe pixel electrode 14. The pixel electrode 14 is separated in each ofthe pixel regions 6. The first substrate 2 is configured of thepartition wall 5, the first base material 10, the element layer 11, theinsulating layer 12, the protective film 13, the pixel electrodes 14,and the like.

The material of the element layer 11 is not particularly limited as longas the material can form semiconductor, and examples thereof can includesilicon, germanium, gallium arsenide, gallium arsenide phosphide,gallium nitride, and silicon carbide. The material of the insulatinglayer 12 is not particularly limited as long as the material has aninsulating property and is readily formable, and a resin material can beused. In the embodiment, for example, a positive photosensitive acrylicresin is used as the material of the insulating layer 12. By using apositive type, an opening to expose a portion of the insulating layer 12can be easily formed. Moreover, the insulating layer 12 has the functionof a planarizing layer so as not to reflect irregularities of theelement layer 11 on the pixel region 6.

The material of the pixel electrode 14 is not particularly limited aslong as the material has conductivity, and examples thereof can include,in addition to copper, aluminum, nickel, gold, silver, and indium-tinoxide (ITO), a material obtained by stacking a nickel film or gold filmon copper foil, and a material obtained by stacking a nickel film orgold film on aluminum foil. In the embodiment, for example, the materialof the pixel electrode 14 is ITO.

The partition wall 5 is disposed on the protective film 13 and theinsulating layer 12, and an electrophoretic dispersion liquid 15 isfilled in the pixel regions 6 defined by the partition wall 5. Thematerial of the partition wall 5 is not particularly limited as long asthe material has proper strength, is readily formable, and is not elutedinto the electrophoretic dispersion liquid 15. A material obtained byadding a cross-linking agent to a resin material such as polyesterresin, polyolefin resin, acrylic resin, or epoxy resin can be used. Inthe embodiment, for example, a negative photosensitive epoxy resin isused as the material of the partition wall 5. By using a negative type,a convex shape can be easily formed. The partition wall 5 is disposed soas to close an opening of the protective film 13. As can be seen fromFIG. 3, the width of the opening of the protective film 13 is narrowerthan the width of the bottom portion of the partition wall 5. With thisconfiguration, a portion where the partition wall 5 and the insulatinglayer 12 are joined together without the protective film 13 can beformed, and the partition wall 5 and the insulating layer 12 can besecurely joined. Moreover, the partition wall 5 and the insulating layer12 are joined together through the protective film 13 on both sides ofthe opening, so that the insulating layer 12 can be prevented from beingdamaged by the electrophoretic dispersion liquid 15 through the opening.

The material of the protective film 13 is not particularly limited aslong as the material has an insulating property and is not eluted intothe electrophoretic dispersion liquid 15. In the embodiment, forexample, silicon nitride is used as the material of the protective film13. The protective film 13 prevents the insulating layer 12 from beingeluted into the electrophoretic dispersion liquid 15. With thisconfiguration, the alteration of the electrophoretic dispersion liquid15 is prevented, and the degradation of the insulating layer 12 isprevented.

The electrophoretic dispersion liquid 15 includes white chargedparticles 16 as charged particles and black charged particles 17 ascharged particles. The white charged particles 16 and the black chargedparticles 17 are dispersed in a dispersion medium 18. The material ofthe white charged particles 16 is not particularly limited as long asthe material is white and chargeable and can be formed into fineparticles. Examples of materials used for the white charged particles 16can include, for example, particles, high polymer, or colloid made of awhite pigment such as titanium dioxide, hydrozincite, or antimonytrioxide. In the embodiment, for example, positively charged titaniumdioxide particles are used as the white charged particles 16.

The material of the black charged particles 17 is not particularlylimited as long as the material is black and chargeable and can beformed into fine particles. Examples of materials used for the blackcharged particles 17 can include, for example, particles, high polymer,or colloid made of a black pigment such as aniline black, carbon black,or titanium oxynitride. In the embodiment, for example, negativelycharged titanium oxynitride is used as the black charged particles 17.For the white charged particles 16 and the black charged particles 17, acharge control agent such as an electrolyte, a surfactant, metal soap,resin, rubber, oil, varnish, or a compound can be added to the particlesas necessary. In addition, a dispersant such as a titanium couplingagent, an aluminum coupling agent, or a silane coupling agent, alubricant, a stabilizer, or the like can be added to the white chargedparticles 16 and the black charged particles 17.

The material of the dispersion medium 18 is not particularly limited aslong as the material has fluidity and is less alterable Examples ofmaterials used for the dispersion medium 18 can include water; alcoholsolvents such as methanol, ethanol, isopropanol, butanol, octanol, andmethyl cellosolve; esters such as ethyl acetate and butyl acetate;ketones such as acetone, methyl ethyl ketone, and methyl isobutylketone; aliphatic hydrocarbons such as pentane, hexane, and octane; andalicyclic hydrocarbons such as cyclohexane and methyl cyclohexane. Inaddition, examples of materials used for the dispersion medium 18 caninclude aromatic hydrocarbons such as benzene, toluene, xylene, andlong-chain alkyl group-containing benzenes. As the long-chain alkylgroup-containing benzenes, hexylbenzene, heptylbenzene, octylbenzene,nonylbenzene, decylbenzene, undecylbenzene, dodecylbenzene,tridecylbenzene, tetradecylbenzene, or the like can be used. Inaddition, as the dispersion medium 18, halogenated hydrocarbons such asmethylene chloride, chloroform, carbon tetrachloride, and1,2-dichloroethane can be used. In addition, examples of materials usedfor the dispersion medium 18 can include oils and a silicone oil. Thesesubstances can be used alone or as a mixture, and further, a surfactantsuch as a carboxylate, or the like may be mixed.

The second substrate 3 is disposed on the partition wall 5 and theelectrophoretic dispersion liquid 15. The second substrate 3 includes asecond base material 21. A common electrode 22 as a counter electrode isdisposed on the second base material 21. A sealing layer 23 as atransparent sealing member that seals the electrophoretic dispersionliquid 15 is disposed on the common electrode 22. The common electrode22 is a common electrode that is disposed over the plurality of pixelregions 6. Thus, the common electrode 22 faces the plurality of pixelelectrodes 14. The second substrate 3 is joined, on the sealing layer 23side, with the partition wall 5. Further, the sealing layer 23 has thefunction of insulating the partition wall 5 from the common electrode22.

The material of the second base material 21 is not particularly limitedas long as the material has a light transmitting property, strength, andan insulating property Examples of materials used for the second basematerial 21 can include glass and a resin material. In the embodiment,for example, a glass plate is used as the material of the second basematerial 21.

The common electrode 22 is not particularly limited as long as thecommon electrode is a transparent conductive film. For example, MgAg,indium-gallium oxide (IGO), indium-tin oxide (ITO), indium-cerium oxide(ICO), indium-zinc oxide (IZO), or the like can be used as the commonelectrode 22. In the embodiment, for example, ITO is used as the commonelectrode 22.

The material of the sealing layer 23 is not particularly limited as longas the material can be joined with the partition wall 5, has a lighttransmitting property and an insulating property, and does not cause thealteration of the electrophoretic dispersion liquid 15. For example,examples of materials used for the sealing layer 23 can includepolyurethane, polyurea, polyurea-polyurethane, urea-formaldehyde resin,melamine-formaldehyde resin, polyamide, polyester, polysulfonamide,polycarbonate, polysulfinate, epoxy resin, acrylic resin such aspolyacrylic acid ester, polymethacrylic acid ester, polyvinyl acetate,gelatin, phenol resin, and vinyl resin. In the embodiment, for example,an ultraviolet-curable acrylic resin or epoxy resin is used.

FIG. 4 is a schematic sectional side elevation showing the structure ofthe electrophoretic display device. As shown in FIG. 4, theelectrophoretic display device 1 is used by applying a voltage betweenthe pixel electrode 14 and the common electrode 22. Then, the voltage ischanged in use between the pixel electrode 14 and the common electrode22.

The common electrode 22 is set at a low voltage relative to the pixelelectrode 14. In this case, since the black charged particles 17 arecharged to a negative voltage, the black charged particles 17 areattracted to the pixel electrode 14. Since the white charged particles16 are charged to a positive voltage, the white charged particles 16 areattracted to the common electrode 22. As a result, the black chargedparticles 17 gather at the first substrate 2, while the white chargedparticles 16 gather at the second substrate 3. When the electrophoreticdisplay device 1 is viewed from the second substrate 3 side, the whitecharged particles 16 can be seen through the second substrate 3. Thus,white display is achieved in the pixel region 6.

The first semiconductor element 7 is disposed in the element layer 11.The first semiconductor element 7 includes a semiconductor film 7 e. Inthe semiconductor film 7 e, a source region 7 h, a channel formingregion 7 k, and a drain region 7 j are formed side by side in thisorder. A gate insulating film 7 f is disposed on the semiconductor film7 e, and a gate electrode 7 g is disposed on the gate insulating film 7f A source electrode 7 n is connected to the source region 7 h, and thevoltage supply line 7 a is connected to the source electrode 7 i. Afirst drain electrode 7 p is disposed to be connected with the drainregion 7 j, and the first through-electrode 7 d is disposed to beconnected with the first drain electrode 7 p. Since the firstthrough-electrode 7 d is connected with the pixel electrode 14, thefirst semiconductor element 7 is electrically connected with the pixelelectrode 14. The control signal line 7 b is connected to the gateelectrode 7 g.

The main material of the partition wall 5 is epoxy resin, and the mainmaterial of the insulating layer 12 is acrylic resin. The insulatinglayer 12 and a portion of the partition wall 5 are joined together.Thus, the joining of the insulating layer 12 and the partition wall 5 isthe joining of the resin materials that are the same as each other,which makes it possible to fix the insulating layer 12 and the partitionwall 5 together at high strength compared with the case where one of theinsulating layer 12 and the partition wall 5 is an inorganic material.The hardness of the partition wall 5 is 2 GPa, and the hardness of theinsulating layer 12 is 0.5 GPa. The partition wall 5 has a higherhardness than the insulating layer 12, and therefore has strength. Forthis reason, even when a load is applied to the partition wall 5 in astep of assembling the first substrate 2 and the second substrate 3together, the deformation or the like of the partition wall 5 isprevented, and the partition wall 5 is less likely to peel from theinsulating layer 12 because the partition wall 5 bites into theinsulating layer 12 side. As a result, it is possible to inhibit thepartition wall 5 from collapsing or crushing.

The hardness of the insulating layer 12 before curing is approximately15 mPa/s, and the hardness of the partition wall 5 before curing isapproximately 2000 mPa/s. Because of this, the material of theinsulating layer 12 can be easily formed into a thin film compared withthe material of the partition wall 5. However, since the insulatinglayer 12 is likely to be eluted into the electrophoretic dispersionliquid 15 compared with the partition wall 5, the protective film 13 isdisposed to cover the insulating layer 12. Since the insulating layer 12and the electrophoretic dispersion liquid 15 are not in contact witheach other due to the protective film 13, the electrophoretic dispersionliquid 15 or the insulating layer 12 can be prevented from beingdamaged.

A portion of the protective film 13 is located between the partitionwall 5 and the insulating layer 12. Specifically, the width of thepartition wall 5 on the insulating layer 12 side is defined as a firstwidth 5 a. The partition wall 5 is joined to the insulating layer 12 atthe center of the partition wall 5 in the width direction of thepartition wall 5. The width of a portion of the partition wall 5 joinedto the insulating layer 12 is defined as a second width 5 b. Forexample, the length of the second width Sb is % that of the first width5 a. The protective film 13 enters between the partition wall 5 and theinsulating layer 12 from the both side surfaces of the partition wall 5.The length of a portion of the protective film 13 entering between thepartition wall 5 and the insulating layer 12 from the side surface ofthe partition wall 5 is defined as a third width 5 c. For example, thelength of the third width 5 c is V; that of the first width Sa. In thiscase, the protective film 13 is located on the insulating layer 12, anda portion of the partition wall 5 is located on the protective film 13.Thus, since the insulating layer 12 is covered by the partition wall 5and the protective film 13, the insulating layer 12 is not exposed in asurface to be in contact with the electrophoretic dispersion liquid 15.As a result, it is possible to inhibit the insulating layer 12 fromcoming in contact with the electrophoretic dispersion liquid 15.

FIG. 5 is a schematic plan view of a main portion for explaining therelationship between the pixel and the partition wall, as the firstsubstrate 2 is viewed from the image display surface 3 a side. As shownin FIG. 5, the first substrate 2 includes one pixel electrode 14corresponding to one pixel 8. The partition wall 5 is disposed tosurround the pixel electrode 14 for one pixel 8. The partition wall 5may not surround the entire periphery of the pixel electrode 14 and maybe partially removed. Then, through the removed place, theelectrophoretic dispersion liquid 15 may move between the pixels 8. Thepartition wall 5 is disposed to surround the pixel electrode 14. In thiscase, compared with the case where the partition wall 5 surrounds aplurality of pixel electrodes 14, the area surrounded by the partitionwall 5 can be narrowed. Then, the strength of the partition wall 5 canbe increased. Thus, even when a load is applied to the partition wall 5,it is possible to inhibit the partition wall 5 from collapsing orcrushing.

FIG. 6 is an electrical control block diagram of the electrophoreticdisplay device. As shown in FIG. 6, the electrophoretic display device 1is connected in use to a controller 24. The controller 24 includes aninput unit 25. The input unit 25 is connected to a device that outputsan image signal representing an image to be displayed on theelectrophoretic display device 1, and receives the image signal. Theinput unit 25 is connected with a control unit 26. The control unit 26is connected with a storage unit 27, a first waveform forming unit 28, asecond waveform forming unit 29, and the signal distributing unit 9.

The control unit 26 is a portion that controls the first waveformforming unit 28, the second waveform forming unit 29, and the signaldistributing unit 9. The storage unit 27 stores, in addition to theimage signal, information used when forming, from the image signal, asignal to be output to the electrophoretic display device 1. The firstwaveform forming unit 28 is connected with the first semiconductorelement 7 through the flexible cable 4, the signal distributing unit 9,and the control signal line 7 b, and outputs a data signal for eachpixel to the first semiconductor element 7. The first semiconductorelement 7 is connected with the pixel electrode 14, and outputs avoltage corresponding to the data signal to the pixel electrode 14. Thesecond waveform forming unit 29 is connected with the common electrode22 through the flexible cable 4 and the signal distributing unit 9, andoutputs a voltage waveform to the common electrode 22.

The signal distributing unit 9 distributes a drive signal to the firstsemiconductor element 7 to change a voltage waveform to be output to thepixel electrode 14. Further, the signal distributing unit 9 transmits avoltage waveform to be output to the common electrode 22.

FIGS. 7 and 8 are schematic sectional side elevations showing thestructure of the electrophoretic display device. As shown in FIG. 7, thecommon electrode 22 is set at a low voltage relative to the pixelelectrode 14. In this case, since the black charged particles 17 arecharged to a negative voltage, the black charged particles 17 areattracted to the pixel electrode 14. Since the white charged particles16 are charged to a positive voltage, the white charged particles 16 areattracted to the common electrode 22. As a result, the black chargedparticles 17 gather at the first substrate 2, while the white chargedparticles 16 gather at the second substrate 3. When the electrophoreticdisplay device 1 is viewed from the second substrate 3 side, the whitecharged particles 16 can be seen through the second substrate 3. Thus,white display is achieved in the pixel region 6.

As shown in FIG. 8, the common electrode 22 is set at a high voltagerelative to the pixel electrode 14. In this case, since the blackcharged particles 17 are charged to a negative voltage, the blackcharged particles 17 are attracted to the common electrode 22. Since thewhite charged particles are charged to a positive voltage, the whitecharged particles 16 are attracted to the pixel electrode 14. As aresult, the white charged particles 16 gather at the first substrate 2,while the black charged particles 17 gather at the second substrate 3.When the electrophoretic display device 1 is viewed from the secondsubstrate 3 side, the black charged particles 17 can be seen through thesecond substrate 3. Thus, black display is achieved in the pixel region6.

Next, a method for manufacturing the electrophoretic display device 1described above will be described with reference to FIGS. 9 to 18. FIG.9 is a flowchart of the method for manufacturing the electrophoreticdisplay device. FIGS. 10 to 18 are schematic views for explaining themethod for manufacturing the electrophoretic display device. In theflowchart of FIG. 9, Step S1 corresponds to an upper electrode disposingstep. This step is a step of disposing the common electrode 22 and thesealing layer 23 on the second base material 21.

Next, the method proceeds to Step S2. Step S2 is an element disposingstep. This step is a step of disposing the element layer 11 on the firstbase material 10.

Next, the method proceeds to Step S3. Step S3 is an insulating layerdisposing step. This step is a step of disposing the insulating layer 12on the element layer 11.

Next, the method proceeds to Step S4. Step S4 is a protective filmdisposing step. This step is a step of disposing the protective film 13on the insulating layer 12.

Next, the method proceeds to Step S5. Step S5 is a lower electrodedisposing step. This step is a step of disposing the firstthrough-electrode 7 d and the pixel electrode 14 on the protective film13.

Next, the method proceeds to Step S6. Step S6 is a partition walldisposing step. This step is a step of disposing the partition wall 5 onthe first substrate 2.

Next, the method proceeds to Step S7. Step S7 is a dispersion liquidfilling step. This step is a step of filling the pixel region 6 with theelectrophoretic dispersion liquid 15.

Next, the method proceeds to Step S8. Step S8 is a substrate assemblingstep. This step is a step of bonding the partition wall 5 and the secondsubstrate 3 together.

Through the steps described above, the steps of manufacturing theelectrophoretic display device 1 are finished.

Next, the manufacturing method will be described in detail using FIGS.10 to 18 in correspondence with the steps shown in FIG. 9.

First, the second substrate 3 is manufactured. FIG. 10 is a diagramcorresponding to the upper electrode disposing step of Step S1. As shownin FIG. 10, the second base material 21 is prepared. As the second basematerial 21, a plate obtained by grinding a glass plate to apredetermined thickness and polishing the plate to reduce a surfaceroughness is used. Next, the common electrode 22 is disposed on thesecond base material 21. An ITO film with a film thickness ofapproximately 100 nm is formed on the second base material 21 using adeposition method such as a sputtering method. Next, the ITO film ispatterned by a photolithography method and an etching method to form thecommon electrode 22.

Next, the sealing layer 23 is disposed on the common electrode 22. Thesealing layer 23 can be disposed using an ink jet method and variouskinds of printing methods such as offset printing, screen printing,relief printing including flexographic printing, and intaglio printingincluding gravure printing. In addition, a spin coating method, a rollcoating method, a die coating method, a slit coating method, a curtaincoating method, a spray coating method, a dip coating method, or thelike may be used.

Subsequently, the first substrate 2 is manufactured. FIG. 11 is adiagram corresponding to the element disposing step of Step S2. As shownin FIG. 11, in Step S2, the first base material 10 is prepared. Also asthe first base material 10, a plate obtained by grinding a glass plateto a predetermined thickness and polishing the plate to reduce a surfaceroughness is used. The element layer 11 is formed on the first basematerial 10. Since the method for forming the element layer 11 ispublicly known, a detailed description is omitted, and the manufacturingmethod will be roughly described. There are multiple methods for formingthe element layer 11, and the forming method is not particularlylimited.

First, a foundation insulating film 30 of SiO₂ is formed on the firstbase material 10 by a chemical vapor deposition (CVD) method. Next, anamorphous silicon film with a film thickness of approximately 50 nm isformed on the foundation insulating film by a CVD method or the like.The amorphous silicon film is crystallized by a laser crystallizationmethod or the like to form a polycrystalline silicon film. Thereafter,the semiconductor film 7 e as an island-like polycrystalline siliconfilm is formed by a photolithography method and an etching method or thelike.

Next, SiO₂ with a film thickness of approximately 100 nm is formed so asto cover the semiconductor film 7 e and the foundation insulating filmby a CVD method or the like to serve as the gate insulating film 7 f. AMo film with a film thickness of approximately 500 nm is formed on thegate insulating film 7 f by a sputtering method or the like, and thegate electrode 7 g having an island-like shape is formed by aphotolithography method and an etching method. Impurity ions areimplanted into the semiconductor film by an ion implantation method toform the source region 7 h, the drain region 7 j, and the channelforming region 7 k. A SiO₂ film with a film thickness of approximately800 nm is formed so as to cover the gate insulating film 7 f and thegate electrode 7 g to serve as a first inter-layer insulating film 11 n.

Next, a contact hole reaching the source region 7 h and a contact holereaching the drain region 7 j are formed in the first inter-layerinsulating film 11 m. Thereafter, a Mo film with a film thickness ofapproximately 500 nm is formed on the first inter-layer insulating film11 m and in the contact holes by a sputtering method or the like, andpatterned by a photolithography method and an etching method, to formthe source electrode 7 n, the first drain electrode 7 p, and wires (notshown).

A Si₃N₄ film with a film thickness of approximately 800 nm is formed soas to cover the first inter-layer insulating film 11 i, the sourceelectrode 7 n, the first drain electrode 7 p, and the wires to serve asa second inter-layer insulating film 11 r. The second inter-layerinsulating film 11 r is patterned by a photolithography method and anetching method to form a contact hole therein.

FIG. 12 is a diagram corresponding to the insulating layer disposingstep of Step S3 As shown in FIG. 12, in Step S3, the insulating layer 12is disposed on the second inter-layer insulating film 11 r. First, aresin film serving as the material of the insulating layer 12 isdisposed. A solution with the acrylic resin dissolved therein is coatedon the element layer 11, and then dried and solidified. The resin filmcan be disposed using an ink jet method and various kinds of printingmethods such as offset printing, screen printing, relief printingincluding flexographic printing, and intaglio printing including gravureprinting. In addition, a spin coating method, a roll coating method, adie coating method, a slit coating method, a curtain coating method, aspray coating method, a dip coating method, or the like may be used.

Next, the resin film is patterned by a photolithography method and anetching method. With this configuration, the outer shape of theinsulating layer 12 and the shape of a through-hole 12 a are patterned.Subsequently, the insulating layer 12 is etched using an etchant to formthe through-hole 12 a.

FIGS. 13 and 14 are diagrams corresponding to the protective filmdisposing step of Step S4 As shown in FIG. 13, in Step S4, a SiN filmwith a film thickness of approximately 500 nm is formed on theinsulating layer 12 and in the through-hole 12 a using a depositionmethod such as vapor deposition or a CVD method. Next, as shown in FIG.14, the SiN film is patterned and etched to form the protective film 13.In the through-hole 12 a, the first drain electrode 7 p is exposed.Further, the insulating layer 12 is exposed in a place where thepartition wall 5 is disposed. The etching method is not particularlylimited, but a dry etching method is used in the embodiment.

FIG. 15 is a diagram corresponding to the lower electrode disposing stepof Step S5. As shown in FIG. 15, in Step S5, an ITO film with a filmthickness of approximately 500 nm is formed on the insulating layer 12and the protective film 13 and in the through-hole 12 a using adeposition method such as a sputtering method. Further, the ITO film isetched by a photolithography method and an etching method to form thepixel electrode 14 and the first through-electrode 7 d The insulatinglayer 12 and the protective film 13 are exposed in the place where thepartition wall 5 is to be disposed. The etching method is notparticularly limited, but a dry etching method is used in theembodiment.

FIG. 16 is a diagram corresponding to the partition wall disposing stepof Step S6. As shown in FIG. 16, in Step S6, the partition wall 5 isdisposed on the exposed insulating layer 12 and the exposed protectivefilm 13. First, a photosensitive resin material serving as the materialof the partition wall 5 is coated on the pixel electrode 14. As thecoating method, various kinds of printing methods such as offsetprinting, screen printing, and relief printing can be used. In addition,a coating method such as a spin coating method or a roll coating methodmay be used Subsequently, the photosensitive resin material is heated,dried, and solidified. Next, the photosensitive resin material ispatterned by a photolithography method and then etched to shape thepartition wall 5. The partition wall 5 of the resin material is disposedto cover the insulating layer 12 in the place where a portion of theprotective film 13 is removed. In this step, the first substrate 2 iscompleted.

FIG. 17 is a diagram corresponding to the dispersion liquid filling stepof Step S7 As shown in FIG. 17, in Step S7, the first substrate 2 withthe partition wall 5 disposed thereon is placed in a container (notshown). Then, the white charged particles 16 and the black chargedparticles 17 are added to the dispersion medium 18 and then stirred toprepare the electrophoretic dispersion liquid 15. Next, theelectrophoretic dispersion liquid 15 is supplied to the pixel region 6using a supply tool such as a syringe. As the method for supplying theelectrophoretic dispersion liquid 15, various kinds of printing methodsor an ink jet method may be used. The electrophoretic dispersion liquid15 is supplied to such an extent that the electrophoretic dispersionliquid 15 overflows the pixel region 6.

FIG. 18 is a diagram corresponding to the substrate assembling step ofStep S8. As shown in FIG. 18, in Step S8, the second substrate 3 isdisposed on the partition wall 5. First, the first substrate 2 suppliedwith the electrophoretic dispersion liquid 15 is placed in a reducedpressure chamber. Next, the second substrate 3 is mounted on thepartition wall 5. Subsequently, the pressure in the reduced pressurechamber is reduced to pressurize the second substrate 3 against thefirst substrate 2. With this state maintained, the sealing layer 23 isirradiated with ultraviolet rays. The sealing layer 23 isultraviolet-curable and functions also as an adhesive, so that thepartition wall 5 and the second substrate 3 are temporarily fixedtogether. Next, by heating the first substrate 2, on which the secondsubstrate 3 is disposed, to solidify the sealing layer 23, the secondsubstrate 3 is fixed to the partition wall 5. Through the stepsdescribed above, the electrophoretic display device 1 is completed.

As described above, the embodiment has the following advantageouseffects.

(1) According to the embodiment, the first base material 10 is disposedwith the insulating layer 12. The partition wall 5 is disposed on theinsulating layer 12. Both the insulating layer 12 and the partition wall5 are formed of a resin material. Thus, compared with the case where oneof the insulating layer 12 and the partition wall 5 is an inorganicmaterial and the other is a resin material, the insulating layer 12 andthe partition wall 5 can be fixed together at high strength. Further,the partition wall 5 has a higher hardness than the insulating layer 12,and therefore has high strength. As a result, even when a load isapplied to the partition wall 5, it is possible to inhibit the partitionwall 5 from collapsing or crushing due to peeling-off from theinsulating layer 12.

(2) According to the embodiment, the protective film 13 protecting theinsulating layer 12 is disposed on the surface of the insulating layer12. Thus, the electrophoretic dispersion liquid 15 is prevented fromcoming in contact with the insulating layer 12. Then, it is possible toprevent the electrophoretic dispersion liquid 15 and the insulatinglayer 12 from being damaged by each other.

(3) According to the embodiment, a portion of the protective film 13 islocated between the partition wall 5 and the insulating layer 12. Thatis, the partition wall 5 closes the opening of the protective film 13.Thus, the insulating layer 12 is not exposed in the pixel region 6. As aresult, it is possible to inhibit the electrophoretic dispersion liquid15 from coming in contact with the insulating layer 12.

(4) According to the embodiment, the first substrate 2 is disposed withone pixel electrode 14 corresponding to one pixel 8. The partition wall5 is disposed to surround the pixel electrode 14. In this case, comparedwith the case where the partition wall 5 surrounds a plurality of pixelelectrodes 14, the area of the place surrounded by the partition wall 5is narrow, and therefore, the strength of the partition wall 5 can beincreased. Thus, even when a load is applied to the partition wall 5, itis possible to inhibit the partition wall 5 from collapsing or crushing.

(5) According to the embodiment, the insulating layer 12 and thepartition wall 5 are made of a resin material, and the values of thethermal expansion coefficients thereof are close to each other. Thus,even when the temperature changes greatly in the manufacturing steps ofthe electrophoretic display device 1, the partition wall 5 can be lesslikely to peel from the insulating layer 12.

(6) According to the embodiment, the force of adhesion between theinsulating layer 12 and the partition wall 5 is high. Thus, even whenthe electrophoretic dispersion liquid 15 expands on heating, it ispossible to inhibit the partition wall 5 from peeling from theinsulating layer 12.

Second Embodiment

Next, an electrophoretic display device according to a second embodimentwill be described using FIG. 19. FIG. 19 is a schematic sectional sideelevation showing the structure of the electrophoretic display device.The second embodiment differs from the first embodiment in that theprotective film 13 is not located between the insulating layer 12 andthe partition wall 5. Parts that are the same as those of the firstembodiment are not described.

That is, in the embodiment as shown in FIG. 19, the electrophoreticdisplay device 33 includes a first substrate 34 and the second substrate3, and has a structure in which the first substrate 34 and the secondsubstrate 3 interpose the electrophoretic dispersion liquid 15therebetween. In the first substrate 34, a protective film 35 isdisposed on the insulating layer 12, the top of the partition wall 5,and the side surfaces of the partition wall 5. It is sufficient, for theprotective film 35 on the side surface of the partition wall 5, to bedisposed to such an extent that the insulating layer 12 is not exposedin the boundary between the partition wall 5 and the insulating layer12, and thus, it is not necessary for the protective film 35 to bedisposed on the entire side surface of the partition wall 5. Theprotective film 35 is not interposed between the insulating layer 12 andthe partition wall 5. Thus, the entire bottom surface of the partitionwall 5 is in contact with and fixed to the insulating layer 12. Thus,since the contact area of the bottom surface of the partition wall 5with the insulating layer 12 is wide compared with the first substrate 2of the first embodiment, the partition wall 5 can be still less likelyto peel from the insulating layer 12.

The protective film 35 is formed by a CVD method or the like after thepartition wall 5 is disposed on the insulating layer 12. Thereafter, thefirst drain electrode 7 p in the contact hole is exposed, and then, thepixel electrode 14 is formed. In FIG. 19, the protective film 35 is alsodisposed on the top of the partition wall 5; however, the protectivefilm 35 on the top of the partition wall 5 may be removed.

Third Embodiment

Next, an electronic apparatus including the electrophoretic displaydevice mounted therein according to a third embodiment will be describedusing FIGS. 20 and 21. FIG. 20 is a schematic perspective view showingthe structure of an electronic book. FIG. 21 is a schematic perspectiveview showing the structure of a wristwatch. As shown in FIG. 20, theelectronic book 38 as the electronic apparatus includes a plate-likecase 39. The case 39 is disposed with a lid portion 41 through hinges40. Further, the case 39 is disposed with operation buttons 42 and adisplay unit 43 as a display device. An operator can operate thecontents to be displayed on the display unit 43 by operating theoperation buttons 42.

Inside the case 39, a control unit 44 and a signal drive unit 45 thatdrives a data signal to the display unit 43 are disposed. The controlunit 44 outputs display data to the signal drive unit 45, and alsooutputs a timing signal when converting the display data into the datasignal. The signal drive unit 45 generates the data signal from thedisplay data, and outputs the data signal to the display unit 43.Moreover, the control unit 44 outputs a display control signal that issynchronized with the data signal output by the signal drive unit 45 tothe display unit 43. The display unit 43 generates a signal necessaryfor electrophoretic display, from the display control signal and datasignal input thereto, in a signal distributing circuit inside thedisplay unit 43, so that it is possible to perform display according tothe display data output by the control unit 44 to the display unit 43.The operation of the operator through the operation buttons 42 isconverted into a signal at the appropriate time, and the signal istransmitted to the control unit 44 and reflected in the output signal ofthe control unit 44. As the display unit 43, any of the electrophoreticdisplay device 1 and the electrophoretic display device 33 is used.Thus, the electronic book 38 can be a device using, as the display unit43, the electrophoretic display device in which the partition wall 5 isless likely to collapse and thus which has an easy-to-assemblestructure.

As shown in FIG. 21, the wristwatch 48 as the electronic apparatusincludes a plate-like case 49. The case 49 includes a band 50, and theoperator can wrap the band 50 around the arm to secure the wristwatch 48to the arm. Further, the case 49 is disposed with operation buttons 51and a display unit 52 as a display device. The operator can operate thecontents to be displayed on the display unit 52 by operating theoperation buttons 51.

Inside the case 49, a control unit 53 that controls the wristwatch 48and a signal drive unit 54 that drives a signal to the display unit 52are disposed. The control unit 53 outputs display data and a necessarytiming signal to the signal drive unit 54. The necessary timing signalmay include a signal directly output from the control unit 53 to thedisplay unit 52. The signal drive unit 54 outputs the signal necessaryfor display to the display unit 52, so that the contents correspondingto the display data can be displayed on the display unit 52. As thedisplay unit 52, any of the electrophoretic display device 1 and theelectrophoretic display device 33 is used. Thus, the wristwatch 48 canbe a device using, as the display unit 52, the electrophoretic displaydevice in which the partition wall 5 is less likely to collapse and thuswhich has an easy-to-assemble structure.

The invention is not limited to the embodiments described above, andvarious modifications or improvements can be added within the technicalidea of the invention by a person ordinarily skilled in the art.Modified examples will be described below.

Modified Example 1

In the first embodiment, the white charged particles 16 and the blackcharged particles 17 are disposed in the electrophoretic dispersionliquid 15. Instead of the white charged particles 16 and the blackcharged particles 17, charged particles of red, green, blue, and othercolors may be used. According to this configuration, color display canbe performed by displaying the red, green, blue, and other colors. Inaddition, only charged particles of one color may be used in theelectrophoretic dispersion liquid 15.

Modified Example 2

In the first embodiment, one pixel electrode 14 is disposed in one pixelregion 6. A plurality of pixel electrodes 14 may be disposed in onepixel region 6. Display can be subdivided.

Modified Example 3

In the first embodiment, the white charged particles 16 are positivelycharged, while the black charged particles 17 are negatively charged.The white charged particles 16 may be negatively charged, while theblack charged particles 17 may be positively charged. An easy-to-controlcharged state may be employed.

Modified Example 4

In the first embodiment, the shape of the pixel region 6 isquadrilateral. The shape of the pixel region 6 may be a circle, anellipse, a polygon, or a shape including an arc and a line. In thiscase, since the partition wall 5 is formed of a resin material, theshape of the partition wall 5 can be easily matched to the shape of thepixel region 6.

Modified Example 5

In the first embodiment, after the electrophoretic dispersion liquid 15is disposed in the pixel regions 6 of the first substrate 2, the firstsubstrate 2 and the second substrate 3 are joined together. In addition,after the pixel regions 6 are communicated with each other and the firstsubstrate 2 and the second substrate 3 are joined together, theelectrophoretic dispersion liquid 15 may be disposed in the pixelregions 6. An easy-to-manufacture step order may be employed.

Modified Example 6

In the first embodiment, the first semiconductor element 7 is disposedin the first substrate 2. A structure may be employed in which the firstsemiconductor element 7 is not disposed in the first substrate 2 butonly the pixel electrode 14 is disposed therein. Then, a drive circuitthat directly applies a voltage to the pixel electrode 14 may beprovided. Since the structure of the first substrate 2 is simplified,the first substrate 2 can be easily manufactured.

The entire disclosure of Japanese Patent Application No. 2015-184810,filed Sep. 18, 2015 is expressly incorporated by reference herein.

What is claimed is:
 1. A display device substrate comprising: asubstrate including an insulating layer; a partition wall disposed onthe insulating layer; a protective film being disposed on a surface ofthe insulating layer, the protective film including an opening, thewidth of the opening being narrower than the width of a bottom portionof the partition wall, the bottom of the partition wall at leastpartially overlapping the opening so that the bottom of the partitionwall and the protective film are in contact.
 2. The display devicesubstrate according to claim 1, wherein the protective film protects theinsulating layer.
 3. The display device substrate according to claim 1,wherein the protective film comprises silicon nitride.
 4. The displaydevice substrate according to claim 1, wherein the insulating layer isformed of a resin material.
 5. The display device substrate according toclaim 4, wherein a positive photosensitive acrylic resin is used to formthe insulating layer.
 6. The display device substrate according to claim1, wherein the partition wall is formed of a resin material.
 7. Thedisplay device substrate according to claim 6, wherein the partitionwall comprises a polyester resin, polyolefin resin, acrylic resin, orepoxy resin.
 8. The display device substrate according to claim 6,wherein the partition wall comprises a crosslinked resin.
 9. The displaydevice substrate according to claim 6, wherein the partition wallcomprises a negative photosensitive epoxy resin.
 10. The display devicesubstrate according to claim 1, wherein the partition wall has higherhardness than the insulating layer.
 11. The display device substrateaccording to claim 1, wherein the substrate includes one pixel electrodecorresponding to one pixel, and the partition wall is disposed tosurround the pixel electrode.
 12. The display device substrate accordingto claim 11, wherein a circuit portion that is electrically connected tothe pixel electrode is disposed between the substrate and the insulatinglayer.
 13. The display device substrate according to claim 1, whereinthe insulating layer is a planarizing layer.
 14. A display devicecomprising: the display device substrate according to claim 1; atransparent sealing member supported by the partition wall; a counterelectrode disposed on the transparent sealing member; a circuit portion,wherein the insulating layer is disposed between the circuit portion andthe partition wall, and wherein the circuit portion is connected to apixel electrode; and an electrophoretic dispersion liquid sealed in aspace formed by the partition wall, the transparent sealing member, andthe protective film.
 15. An electronic apparatus comprising: the displaydevice according to claim 14; and a control unit that controls thedisplay device.
 16. A method for manufacturing a display devicecomprising the steps: providing a first substrate comprising a firstbase material and an element layer; disposing an insulating layer of apositive photosensitive acrylic resin material on the element layer;disposing a protective film on the surface of the insulating layer;removing a portion of the protective film; and disposing a partitionwall of a resin material to cover the insulating layer at a place wherethe portion of the protective film is removed, the partition wallforming partitioned rooms; filling the partitioned rooms with anelectrophoretic dispersion fluid; providing a second substratecomprising, in order, a second base material, a common electrode, and atransparent sealing member; bonding the transparent sealing member ofthe second substrate with the partition wall.
 17. The method formanufacturing a display device of claim 16, wherein the partition wallcomprises a polyester resin, polyolefin resin, acrylic resin, or epoxyresin.
 18. The method for manufacturing a display device of claim 17,wherein the partition wall comprises a negative photosensitive epoxyresin material.
 19. The method for manufacturing a display device ofclaim 16 further comprising the step of patterning the photosensitiveresin material of the partition wall using photolithography.
 20. Themethod for manufacturing a display device of claim 14 further comprisingthe step of patterning the photosensitive resin material of theinsulating layer using photolithography.